1. Field of the Invention
The present invention relates to a disc clamping apparatus clamping a recording/reproducing medium in a disc drive, and more particularly, to a disc clamping apparatus clamping recording/reproducing media having various thicknesses.
2. Description of the Related Art
In general, a disc drive, which records information on a disc and reproduces the information from the disc, includes a disc clamping apparatus clamping the disc so that the disc securely rotates.
FIG. 1 is an exploded perspective view of a conventional disc drive, and FIG. 2 is a cross-sectional view of the conventional disc clamping apparatus of FIG. 1.
As shown in FIG. 1, a disc drive 1 includes a disc cartridge 10, a tray 20, a deck 30, a disc clamping apparatus 40, and a cover 50. The disc cartridge 10 has upper and lower cases 11 and 12, which form an inner space containing a disc D. A turntable 31 supporting the disc D and a pickup device 32 detecting information recorded on the disc D are installed in the deck 30. The disc clamping apparatus 40, as shown in FIG. 2, includes a clamper 41, a clamper plate 47, a clamper holder 42, a magnet 44, and a plate 33. The clamper 41 clamps the disc D, which is placed on the turntable 31. The clamper plate 47 supports the clamper 41 so that the clamper 41 is moveable. The clamper holder 42 is combined with the clamper 41. The magnet 44 is installed between the clamper 41 and the clamper holder 42. The plate 33 is mounted on in the turntable 31, and a magnetic attractive force operates between the plate 33 and the magnet 44. A magnet back yoke 45 condenses a magnet flux that occurs from the magnet 44.
In the conventional disc drive having the above-described structure, a process of clamping the disc D using the disc clamping apparatus 40 will be described with reference to FIGS. 1 and 2.
When the disc cartridge 10 containing the disc D is loaded on the tray 20 and inserted into the deck 30, a protrusion 21 formed on one side of the tray 20 pushes up an intervening portion 47a of the clamper plate 47 to rotate the disc clamping apparatus 40 in a direction to clamp the disc D. Also, in response to the insertion of the tray 20 into the deck 30, the turntable 31 is raised upward, and the disc D is in a secure placement state on the turntable 31. The clamper 41 moves in a clamping direction toward the turntable 31 due to the magnetic attractive force between the magnet 44 and the plate 33 to clamp the disc D and the turntable 31 together. Thus, the disc D is prevented from moving or separating from the turntable 31 due to a clamping force of the clamper 41. The clamper 41 rotates together with the disc D according to a rotation of the turntable 31 while the disc D is clamped to the clamper 41.
When the tray 20 comes out of the deck 30, the turntable 31 moves in an opposite direction of the clamper 41. Thus, the clamper 41 is separated from the disc D.
As described above, the conventional disc clamping apparatus only clamps a disc having a certain thickness. Thus, if the disc clamping apparatus clamps a thinner or thicker disc than a particular disc having the certain thickness, the disc is not precisely clamped nor securely clamped, and this results in an insecure rotation of the disc.
Discs that are recording/reproducing media become smaller and thinner in accordance with a current development trend of the discs using a high-density recording technique. Also, to meet consumers' demands for slimming disc drives, the thickness of the discs will be thinner.
However, the conventional disc clamping apparatus can clamp only the disc having the certain thickness, but can not clamp discs having various other thicknesses. Thus, a new disc clamping apparatus clamping discs having different thicknesses is needed.